With rapid expansion of the markets of, for example, mobile tablet terminals, smartphones, electric vehicles and stationary power storage systems, secondary batteries which are safe, long in life time and high in energy density have been demanded. As candidates for such secondary batteries, a lithium ion secondary battery, which has high in energy density and free from the memory effect, is regarded as one of the promising secondary batteries. In particular, recently, attention has been paid to the so-called self-discharge property in which the charging capacity does not decrease even under standby condition in a charged state, as a key item to determine the degree of superiority or inferiority of a battery. Examples of the technique to achieve safe, long in life time and high in energy density lithium ion secondary batteries include: a method using a safe lithium-manganese composite oxide-based positive electrode, a method using a relatively inexpensive carbon-based negative electrode, and a method using a nonaqueous electrolyte solution excellent in stability. In particular, a technique using an excellent electrolyte solution and an excellent additive is important. The reasons for this are described below.
In the charge-discharge of a lithium ion secondary battery, the desorption and absorption reaction of lithium ions occurs in the interface between the electrode and the electrolyte solution. At this time, other than these reactions, decomposition reactions of an electrolyte solution solvent and a supporting electrolyte salt may take place in some cases. The decomposition reaction forms a high-resistance film on the electrode surface, and inhibits the desorption and absorption reactions of lithium ions, which should occur primarily. It is known that as a result, the irreversible decrease of the discharge capacity is progressed, and the properties as a secondary battery are degraded.
Various methods have been devised in order to suppress such a degradation. As one of such methods, there is mentioned a method in which the above-described decomposition reaction is suppressed by forming a protective film on the electrode surface; and as a technique for this purpose, there has been proposed addition of a cyclic disulfonic acid ester to the electrolyte solution as an additive to the electrolyte solution having film forming ability.
On the basis of what has been described above, a technique to suppress the degradation of the properties of a secondary battery, in particular, some techniques to improve the cycle characteristics and some techniques to suppress the internal resistance of a secondary battery during storage have been disclosed. Patent Literature 1, Patent Literature 2 and Patent Literature 3 disclose, as a method for suppressing the decomposition reaction of the electrolyte solution by forming a protective film on the electrode surface, a technique using an electrolyte solution of a secondary battery comprising a cyclic sulfonic acid ester having at least two sulfonyl groups, and a technique using a cyclic or linear disulfonic acid ester having an unsaturated bond.
Patent Literature 4 describes a lithium ion secondary battery having an electrolyte solution including a linear disulfonic acid ester and a cyclic disulfonic acid ester and having a negative electrode comprising one type of carbon material as a negative electrode active material. Patent Literature 5 describes a lithium ion secondary battery using amorphous carbon as the negative electrode active material and comprising an electrolyte solution comprising methylene methanedisulfonic acid ester. Patent Literature 6 describes a lithium ion secondary battery provided with an electrolyte solution including a cyclic sulfonic acid ester.